LTE Protocols and Procedures

3 days

Download brochureThe course provides a complete overview of the LTE protocols and procedures covering completely E-UTRAN and partly EPC signaling. It follows the top down approach, investigating LTE signaling corresponding to the layers from L3 down to L1, including NAS, RRC, PDCP, RLC, MAC and PHY. Subsequently, signaling related to the new interfaces, namely S1, X2, S11, S5/S8 and S10 is explained in great detail. The course is concluded with the presentation of the IMS nodes and key procedures and discussion of interoperability with other 3GPP and non-3GPP networks.

Introduction to EPS

• Evolution steps of the 3GPP systems, the goals for LTE
• LTE bandwidths, bit rates and UE categories

EPS Network Architecture

• E-UTRA and Evolved Packet Core network architecture
• Nodes: UE, eNB, SGW, MME, PGW, PCRF
• Interfaces: Uu, X2, S1, S11, S5, Gx, S6a, SGi, Rx
• Overview of EPS protocols: PDCP, RRC, GTP, X2AP, S1-AP, S1-MME, GTP, Diameter
• IP connectivity, user plane and control plane
• Access Stratum signaling and Non-Access Stratum signaling
• E-UTRAN protocol stack and channel architecture
• E-UTRAN L3 and L2 protocols: RRC, PDCP, RLC, MAC, PHY

Non-Access Stratum (NAS) Protocols

• NAS protocols (EMM and ESM)
• UE states and state transitions (LTE-idle, LTE-active, LTE-detached)
• Subscriber identities and their relations (IMEI, IMSI, GUTI, STMSI, RNTIs)
• Security and keys' derivation
• Integrity and Encryption - SNOW 3G, AES
• EPS Authentication and Key Agreement; Key Hierarchy
• Key distribution and mobility
• NAS message structure

Radio Resource Control (RRC) Protocol

• RRC procedures including system info broadcasting, paging, RRC connection establishment, security establishment, NAS message transport and RRC connection reconfiguration
• Types of radio bearers
• RRC States & State Transitions

Packet Data Convergence Protocol (PDCP)

• PDCP architecture
• PDCP Functions (robust header compression, ARQ at handover, status reporting ciphering and integrity protection)
• PDCP message structure for Data and Control

Radio Link Control (RLC) Protocol

• RLC architecture (Transparent Mode, Unacknowledged Mode, Acknowledged Mode)
• Functions (segmentation / concatenation, ARQ procedures)
• RLC PDU formats (RLC user plane and control PDUs)

MAC Protocol

• MAC Architecture
• MAC PDU: user plane and control plane parts
• Scheduling procedures for downlink and uplink resource assignments
• Scheduling Requests, Buffer Status Reports and Power Headroom Reports
• Hybrid-ARQ processes and HARQ operation
• Mapping of Logical Channels to Transport Channels
• MAC level identities mapping

LTE PHY Layer

• Logical, Transport and Physical channels and their relation to the radio interface protocol stack (i.e. Channel architecture)
• Adaptive Modulation and Coding, QPSK, 16-QAM, 64-QAM
• Principles of OFDM/OFDMA/SCFDMA
• Principles of MIMO
• Downlink and uplink frame structure and its elements (PRB, RE, CCE)
• L1 control information, formats and signaling
• Resource mapping to radio frame
• PHY layer related scheduling principles (including ”maximum SNIR”, ”round robin” and ”proportional fair” schedulers)

S1 Interface Procedures

• S1 CP and UP protocol stacks
• S1 Application Protocol (S1-AP)
• S1-AP identifiers
• S1-AP procedures: S1 association and SON related procedures, UE related procedures
• GTP-U protocol (including tunneling concept and TEID)

X2 Interface Procedures

• X2 CP and UP protocol stacks
• X2 Application Protocol (X2-AP)
• X2-AP identifiers
• X2-AP procedures: X2 association procedures, UE related procedures, SON related procedures

S11, S5/S8, S10 Interface Procedures

• CP and UP protocol stacks for each interface
• GTP-C (eGTP) protocol
• GTP-C message header and tunneling concept
• Functions and procedures related to each interface (UE context exchange, call establishment, bearer management, etc.)

IMS and End-to-End Signaling

• IMS architecture (S-CSCF, P-CSCF, I-CSCF, HSS, AS, etc.)
• IMS security and PCC considerations
• SIP Basics - registration, session establishment
• IMS end-to-end protocol stack
• IMS end-to-end call establishment
• Voice in LTE (CS Fallback, Voice Call Continuity, VoLGA)